Circuit breakers



Feb. 2, 1960 A. R. NORDEN 2,923,788

CIRCUIT BREAKERS Filed July 5, 1957 3 Sheets-Sheet 1 INVENTOR ALEXANDER R. NORDEN ATTY.

Feb. 2, 1960 A. R. NORDEN 2,923,788

CIRCUIT BREAKERS Filed July 5, 1957 3 Sheets-Sheet 2 INVENTOR ALEX AN DER R. NORD EN ATTY.

Filed July 5 1 A. R. NORDEN CIRCUIT BREAKERS 5 Sheets-Sheet 3 INVENTOR DER R. NORDEN ALEX BY fi United States Patent CIRCUIT BREAKERS Alexander R. Norden, New York, N.Y., assignor to Fede'i'al Pacific Electric Company, a corporation of Delaware Application July 3, 1957, Serial No. 669,808 20 Claims. Cl. 200-44 The present invention relates to automatic circuit breakers.

In one aspect the present invention relates to the reduction of the elfort required to operate circuit breakers and in particular manually operatedcircuit breakers. This feature is of particular importance in connection with the relatively small and low-cost form of circuit breakers used in entrance service equipment and in lighting panelboards. In such circuit breakers, it is customary to provide simple shaft-and-bearing connections in the operating linkage between the operating handle and the operated moving contact member. The stress and the corresponding friction at each of the bearings is likely to be high, particularly where the closing operation of the handle is accompanied by compression of a contactopening spring. The friction developed may be expected to be especially high between a metal part pivoted in a part made of molded insulation. An object of the present invention is to reduce the friction involved, both to minimize wear and to minimize the effort required for operation.

In more specific aspect, the present invention relates to an improvement in circuit breakers having a releasable toggle or the like as disclosed in an application entitled Multi-pole Circuit Breakers, Serial No. 669,881, filed by Paul S. Martin concurrently herewith. .In that application there is disclosed a circuit breaker which identical with the circuit breaker described herein below and shown in the accompanying drawings, wherein an oscillating handle is arranged to drive ato ggle forming part of the drive linkage of the circuit breaker. I During'such operation that toggle is intended to function as athrusttransmitting unit, and the handle applies the thrust to a link of that toggle. The organization is such that, as the toggle is advanced by the handle in closing the circuit breaker, the handle swings through an arc and tends to rotate one link of the toggle. The tendency toward rotation is such that the toggle tends to collapse, and thereby tends to defeat efforts to operate the circuit breaker manually. It was intended, as previously mentioned, that the toggle shall remain locked and act as a single link in the drive linkage. An object of the present invention is to overcome any tendency of the arcuate motion of the handle to buckle the toggle in such a linkage.

The foregoing objects are achieved in the illustrative embodiment described in detail below and shown in the accompanying drawings. In that embodiment, briefly,.the

operating element that is articulated to one of the toggle links is provided with a pin or shaft and the toggle link which is directly engaged by the handle'is provided with a slot in which the pin operates. The pin in this embodiment is shown round and the slot is shown'as having slightly curved sidewalls, although it will be understood that, in broad aspect a variety of other shapes:

may be used whereinthe driving element rolls or rocks against the driven element for avoiding rubbing friction without resort to ball hearings or similar added antifriction devices. In the illustrative embodiment, at the start of thecir cuit breaker closing operation the pin or shaft is at one [end of the slot and, because of the thrust applied by the handle, the pin or shaft rolls along one wall of the slot and travels to the opposite end of the slot, in completing the operating stroke of the mechanism.

A more specific feature of the invention is the provision o'f aspring device for insuring that the pin will be at the desired end of the slot at the start of operation so that the rolling contact will befrealized throughout the operating stroke. An additional feature is the provision of a spring arranged to insure the desired straight or locked configuraticn of the toggle at the start of a contact-closing operation of thehandle. In the illustrative embodiment, a single spring acts .both to bias the toggle link to the starting end of its slot and to bias the toggle straight. As a still further valuable feature, this spring device is specially arranged to be of no effect when the circuit breaker is closed, thereby to avoid interference with release of the toggle when, the toggle is to be released in automatic opening of the circuit breaker. This feature thus provides a highly sensitive toggle, readily responsive to toggle-releasing control eifort The nature of the invention and its further objects and features of novelty will be, better appreciated from the following detailed description of .the illustrative embodirn nt which is shown in the accompanying drawings forming part of this disclosure. In the drawings:

Figs. 1 to 4 are the side views of an end pole of a three-pole circuit breaker, with the parts thereof in various operative positions, the cover being removed and certain parts being shown in fragmentary section. In Fig; l the mechanism is shown in the contacts-closed position; in Fig. Zthe mechanism is shown in its open position,'ready for reclosing; in Fig. 3 the parts are shown at the instant of overload release; arid Fig. 4 is a view of the mechanism of Fig. l in the position. itoccupies afteroverload release and openingof the contacts, with the operating handle of the circuit breaker manually held in its fen? position, during overload release. 7

Figs. j5 and 6 are side views of the center pole of the illustrative three-pole circuit breaker as the parts thereof appear in the diiferent phases of operation corresponding to Figs. 3 and 4 respectively.

, Fig. 7 is a fragmentary transverse section of the illustrative multi-pole circuit'breaker along the line 7-7 of Fig. 1."

Fig. 8 is a plan view of a trip bar looking upward in Fig; 7.

Fig. 9 is a cross-sectional view of the trip bar in Fig. 8 along the line 9-9 therein,

Fig. 10 is an end view of the trip bar in Fig. 8.

Figures ll, 12 and 13 are successive cross-sections of the trip bar in Fig. 8 along the lines 1111,1212, and 13-'13 in Fig. 8.

Figs. 14, 15 and 16 are enlarged fragmentary crosssectional views of two of the elements of Figs. 1 to 4 in variousoperational configurations thereof.

, Fig. 17 is a fragmentary cross-section of a portion of the mechanism in Fig. 4 along the line 17-17 therein. Referring first to Fig. 7 there is shown a fragmentary cross-section of a three-pole circuit breaker embodying also'tru'e of walls 22 and 24. Each cavity 10, 12 and 14 contains a complete circuit-breaker mechanism, including a pair of contacts, a contact-opening linkage and an overload release means; and a novel common release means forms part of each pole of the three-pole circuit breaker, as will be seen in connection with the discussion of Figs. 1 to 6 inclusive below. A common operator for all three poles is provided, including moldedmembers 28, 3li'and 32 of insulation having square holes receiving metal shaft 34, which is of square cross-section. Members 28 and 32 are journaled in the outside casing walls '16 and 26, respectively, and each member 28, 30 and operator have depending molded portions 28a and 32a (see Figs.7 and 8). Members 28 and 32 contain U- shaped metal members 36, which members are wholly concealed within those molded members except for a projecting pivot portion 36a. Common trip bar 38 for all the poles (Figs. 7-11) has a pair of end openings 40 which receive portions 36a of the composite manual operator.

I Trip bar 38 has three bearing apertures for three U- shapedwire members 42. In Fig. 7 these members 42 are designated 42a, 42b and 420 to distinguish the three poles, and these designations are used in Figs. l-4, and

in 5 and 6, respectively. When the composite member 4 28-3tl32-34 is oscillated by manipulation of handle 30a, U-shaped members 36 operate the common trip bar 38 and, acting through members 42, operate the separate mechanisms of the three poles for opening and closing the contacts, and in resetting, as will be seen.

The mechanism of each pole is the same as the mechanism for each of the other poles, to the extent that all are operated by respective members 42, being in turn operated by the common trip bar 38 and the composite manual member described. One of the mechanisms'appears in Figs. 1 to 4 and another, duplicate mechanism, is shown in Figs. 5 to 6.

In Figs. 1 to 4 there is shown a first terminal 44 rigidly carrying a stationary contact 4-6. Movable contact 48 engages contact 46 when the circuit breaker is closed, movable contact 48 being supported on elongated contact-carrying arm 50 that is pivoted near its center on a transverse 'coil spring 52 (see Fig. 17). Carried on pivot 54 in an insulating bearing (not shown) at theend of contact arm 50 remote from contact 48, is an actuator 56 having a bearing 58 which receives the U- shaped wire member 42a mentioned above. An ambient temperature compensating bimetal 60 has its upper end curved about bearing 58 and its lower end is slidably guided by a formed portion of member 56 so that the lower tip of bimetal 60 is projected to a variable extent in dependence on the ambient temperature.

A current responsive bimetal 62 is joined to contact carrying arm 50 at the left-hand end and at its free 365,818, filed July3, 1953, by Thomas M. Cole.

The end pole of the circuit breaker is shown closed in Fig. 1. An electrical circuit may be traced through the circuit breaker from terminal 44 across contacts 46 b and 48, into moving contact carrying arm 50, via bimetal. 62 and braid 64 to terminal 66. There is no current-. bypass path bridging bimetal 62 by virtue of the insu- 4 lated pivot 54 which is more fully disclosed in Patent 2,647,186, issued July 28, 1953, to Thomas M. Cole.

To provide for snap-closing operation, V-shaped member 68 is rockably carried on contact arm 50. Manual operating member 28 has a projection 70, and between this projection and the V-shaped member 68 there is a compression spring 72, which biases movable contact member 50 in the opening direction. With handle 30a in the position illustrated that handle is locked in its on position (as shown in Fig. 1) by a locking toggle consisting of one part 3628 and another part 38-42 whose knee 36a is overset. The angle of overset of this locking toggle is limited by handle engagement with the enclosure. The circuit breaker is shown 0 or open in Fig. 2. In that position, member 68 is rocked counterclockwise by compression spring 72 and handle 30a as well as all other parts of the composite manual operator 28, 30, 32 and 34 are biased in their open direction by springs 72. Contact arm 50 is also biased open by spring 72.

The operation of the mechanism thus far described is as follows. During the closing stroke of handle 3011, the elements named a locking toggle function as an operating or a driving linkage. The composite'handle 28-303234 operates trip bar 38 from the position in Fig. 2 toward the right, bodily, and this in turn pushes wire elements 42 to the right, urging actuator 5660 clockwise until the lower tip of bimetal 60 engages the tip of. bimetal 62. After this point, further operation of the handle, the trip bar 38 and element 42 (element in 42a in Figs. 1-4) drives the latched triangular assembly 50, 56-60, and 62 clockwise about pivot 52 until the left-hand arm of element 68 is arrested by shoulder 74. Continued operation of handle 30a cannot drive contact 48 any further, but is effective to displace member 50 and to bias spring 52 into its downward sagging condition illustrated in Fig. 17. Before handle 30a reaches its full on position, handle portion 70 shifts spring 72 to rock V-shaped member 68 to the right and out of engagement with shoulder 74. At that instant, contact member 50 is quickly propelled clockwise to close the contacts. Spring 72 is much softer than spring 52 and the latter providesthis snap acting contact-closing impetus.

Spring 52 also provides for over-travel. It will be understood that the contacts46, 48 must engage each otherv when the circuit breaker is closed and this overtravel is provided for insuring such engagement despite erosion of some of the contact material during use and despite usual dimensional variations of the assembled parts in production. With the mechanism as shown in Fig. 1, spring 52 is stressed and biases the contacts closed; and the contacts remain closed during the initial part of the opening operation until this stress is released. The operating linkage has an over-travel in the closing direction which corresponds to that part of the opening st'roke'during which the contacts remain closed.

Tripping of the circuit breaker for automatic opening in event of over-load may result from heating of bimetal 62 which deflects its free right-hand extremity downward. Additionally there is provided a soft iron core 76 which is united to member 58 at its left-hand end, at the same place where member 62 is secured. In the event of a heavy surge. of current through bimetal 62, the magnetic field of this current in threading through core 76 produces a force of attraction Which deflects the free end of bimetal 62 downward so as to effect release of the circuit breaker. Additional arrangements for effecting over-current release of circuit breakers of comparable construction are shown in application Ser. No. 353,741, filed May 8,- 1953, and application Ser. No. 590,712, filed June 11, 1956, by Thomas M. Cole.

In the event of an overload and downward deflection of the latch end of bimetal 62 as a result of such overload, actuator 56-60 is released, and is referred to at '5 times as a releasable member, bimetal 62 acting as a latch. Upon freeing of the releasable members 56-60, coil spring pivot 52 very quickly snaps straight and drives member 50 counterclockwise about the engaged contacts 46, 48 as a fulcrum. In so doing member 50 lifts members 56 and 42a. Trip bar 38 has a portion 38a which rests on member 42a and by virtue of this engagement, the lifting of member 56 upon tripping also lifts trip bar 38 so as toswing that trip bar counterclockwise about pivot portion 36a of wire member 36. As will be seen below, the counterclockwise operation of member 38 as just described is efiective to trip the other poles of the circuit breaker. This tripping operation of the related poles, other than this pole which has been considered released by an overload, is effective while the contacts of the overloaded pole remain closed. Members 38 and 42a constitute a release toggle which is locked or straight (rather than buckled), and the toggle of the overload-release pole remains in this condition during the release of the other poles.

i In Figs. 1 to 4 as described above there is a series of phases of operation of one single pole of the i nulti-pole circuit breaker, presumed to be overloaded. Figs. 1, 2 and 3 have been described as representing the circuit breaker closed, open, and at the instant of tripping. Fig. 4 illustrates a further phaseof the circuit breaker operation that might occur. This illustrated condition is the result of holding the circuit breaker closed against a short circuit, as may arise when the circuit breaker is closed on a short circuit. Under such conditions, handle 30a is inevitably held closed after overload release is effective. Release of the other poles (as described below) lift-s trip bar 38 and operates elements 38 and 42d relative to each other, to assume the configuration illustrated in Fig. 4. As seen in Fig. 4, the contacts are fully open even though the handle is in its on position: When the handle is thereafter released, spring 70 is effective to bias the handle clockwise toward the open position. If some frictional detent is present providing interference against the free return of the handle to the full off position, the handle will be arrested at an intermediate position, to indicate the tripped condition of the circuit breaker. If there is no such obstruction, the composite operating member 28, 30, 32 and 34 will be returned to its full off position after the person operating the circuit breaker releases handle 30a. The circuit breaker will then be in reset and in its normal off condition. In the event that a frictional obstruction is provided, the handle can be manually reset from its intermediate trip-indicating position into the off position in order to reset actuator 56-60 to the required position for 'reclosing the contacts, as represented in Fig. 2.

The toggies consisting of trip bar 38 and wire elements 42 may assume various configurations, as mentioned above, either buckled as in Fig. 6,'or straight and locked as in Fig. 1. At the start of a closing stroke of operation of the handle 30a, it is desirable that the toggle consisting of elements 38 and 42a, 38 and 42b, and 38 and 420, should in each instance be locked. For the purpose of assuring that this will be the case, trip bar 38 has a double-headed rivet slidably received therein (Fig. 13) with a compression coil spring 80 between the upper head of that rivet and the trip bar 38. When the handle 38a is in the oi? position (Fig. 2) rivet 78 and compression spring 88 bear against element 30 of the composite operator structure so as to bias trip bar 38 clockwise about its supporting pivots 36 and thereby press portion 38a against each of the toggle members 42a, 42b, and 42c. V

In the condition of the release toggle 38-4211 shown in Fig. 2, there is an overset angle between the line-ofcenters'o'f member 42a compared to the line-of-cen-ters of bearing 58 and pivot portions 36a of member 36, and the release toggle is locked or straight as opposed to buckled (Figs. 4 and 6.for example).

When the handle is rotated from it's olf position illustrated in Fig; 2 to its on position illustrated in Fig. 1, it rotates through an angle of approximately 60. Member 36a which is a round shaft projecting into opening 40 of the trip bar 38 also rotates through this same number of degrees. If opening 40 were a simple round bearing for receiving portion 36a, and if appreciable friction were present, then there would be a torque tending to rotate member 38 counterclockwise with handle 30a as the handle is operated toward the on position. This counterclockwise rotation is in the direction to buckle the release toggle, which is to remain straight or locked during the on operating stroke.

For avoiding the frictional torque tending to buckle the release toggle, opening 40 is formed as an elongated slot and provides a bearing surface over which the pivot portion 36a of element 36 may roll. The rolling travel of portion 36a from the off position to the on posi tion during which it rolls along one wall of opening 40 is illustrated in Figs. l4, l5 and 16. In these figures, the pivot of composite manual operator 28, 3t 32 and 34 is diagrammatically represented by the numeral 82. Fig. 14 shows the relationship of members 38 and the line-of-centers S2-36d in the off condition of the circuit breaker (Fig. 2). Fig. 16 shows the relationship of trip bar 38 to the line-of-ce'nters 8236a in the on condition of the circuit breaker (Fig. 1). Fig. 15 represents an intermediate operative position between the extremes of Figs. 14 and 1 6. During its advance to the right in these figures, element 36a is seen to rotate counterclockwi'se through an angle of about 60. At the same time member 38 is seen to rotate clockwise through an angle of about 60. The relative rotation is thus about 120".

At the start of the on stroke, element 36a presses against the right-hand wall of elongated opening 40 in trip-bar 38. During the on stroke and incidental to the rotation of axis 82-38a (corresponding to handle rotation) relative to the trip bar 38 that also rotates through a substantial angle, element 36a rolls along the right-hand wall of slot or elongated opening 40. This rolling action eliminates risk of troublesome friction that might otherwise develop between element 36a and trip bar 38, and thereby eliminates the possibility of friction buckling the release toggles 38-4211 or 3842b or 38-42c. The slot 40 may thus be considered to be a frictionless bearing for the pivot 36a. The walls 40a (Figs. 14-16) of slots 40 against which pivot pins or shafts 36a press during rolling travel are formed as an are about pivots 58. in this way, actuating thrust is maintained in line with the end pivots of toggle(s) 3$-42.

During the advance of these parts from the off to the on position, the center of element 36a which is an end pivot of the release toggle, shifts in relation to the lines established by the extremities of elements 42a, 42b, and 420. At the outset, the release toggle 38-42 is considerably overset so as to have an angle of about 20 between the line joining element 36a and bearing 58 and the line established by element 42; At the end of the on stroke, there is still an over-set angle of about 6". This angle, while apparently somewhat critical, is easily maintained in manufacture because it is established almost entirely by the shape of the trip bar.

It is important if this rolling action is to occur con-' sistently that element 36a should be reliably positioned initially at the top of the elongated slot 40. Otherwise the rolling action would not occur through the lengths of strokes and the degree of relative rotation described. The rivet 78 and its coil compression spring 80 previously described is effective not only to straighten the release toggle 38-42 but additionally to bias the common trip bar 38 into the desired starting position, that is, to insure starting of element 36a in the top of the elongated slot The bearing in member 38 that is provided for one leg of each member 42a, 42b, and 420, may be termed the knee of the release toggle which is over-set or .straight or locked during the ofi-to-on operating stroke of handle 30a. During this closing stroke of operation, each release toggle 38--42 is a driving link which may be regarded asv a single element. This driving element interconnects the composite operating handle and the separate actuators 56. Thrust is transmitted from the composite handle by way of each locked release toggle 38- 42 to the related actuator 56 which applies pressure against the end of bimetal 62; and after engagement of the actuator 5660 with bimetal 62, the element 56-60 actuates the contact bearing arm to effect closing of the contacts.

Notably each pole includes its own actuator 56-60 that is releasable by deflection of the current-responsive element 62. The pressure of each element 56'60 against the current-responsive element 62 is the latch pressure, a factor that partly determines the current level at which tripping occurs. In this three-pole circuit breaker, each pole includes its own releasable currentresponsive latch 62 and the latch pressure of each pole is not appreciably influenced by the latch pressure developed at the other poles. In order for each currentresponsive bimetal 62 to deflect, it is only necessary to overcome its individual latch pressure.

With the above background, rnultipole operation may be explained. Referring to Figs. 1, 2, 3 and 4, it is seen that the casing wall 18 is provided with an opening 84, and (Fig. 7) an aligned opening is also provided in each internal wall 20, 22 and 24 of the enclosure. These aligned openings provide the space for the composite actuating member 28, 30, 32, 34 and, for the common trip bar 38 which extends across all of the three poles. Figs. 1-4 illustrate the eifect of an over-load released pole on trip bar 38. Figs. 5 and 6 illustrate how the trip bar functions in a pole that is not overloaded when (Fig. 3) one of the poles is overloaded and released by its bimetal. Fig. 3 illustrates how common trip bar 38 is swung counterclockwise through a limited angle in response to release of the actuator 56-60 of that pole. This counterclockwise swing of member 38 is seen in Fig. 5 to cause portion 38a of the trip bar 38 to be lifted away from element 42b of the center pole, that is, to trip the release toggle of the center pole. In this condition the thrust developed between member 56 and element 36a of that center pole causes release toggle 38- 42b to buckle and allow the contact arm 50 of the non-overloaded pole to operate in a contact-opening stroke. This operation takes place even though the handle is held on as illustrated in Fig. 6. If the handle is allowed to return to its off position under the influence of the compression spring 72 of that mechanism, then the mechanism returns to the off position that is normal as illustrated in Fig. 2.

In Figs. 8 to 12 inclusive there are shown a number of views of the trip bar which is formed in a manner to facilitate manufacture and assembly. Trip bar 38 is formed of one piece as a molded insulator. At the lefthand side of Fig. 8 portion 28a of the operating element 28 is shown with its wire member 36 inserted into the opening 40 at one end of the trip bar 38. At the righthand extremity of Fig. 8 the other element 36a carried by element 32, 32a is in condition for insertion into the opposite opening 40.

At the left-hand extremity of Fig. 8, the release toggle element 42a is shown in dotted lines before insertion; and from this position it is advanced axially into its bearing in element 38 and then it is rotated 90 to assume the full-line position illustrated. This motion is perhaps better illustrated in Fig. 9. Elements 42b and 42c, are inserted similarly, a recess '86 being provided to accommodate this assembly operation.- At the time of insertion, each element 42 is advantageously part of the subassembly 50-56-60-452. The leg of each element 42 that extends through bearing 58 in member 56 isswaged with a head as shown in Fig. 7 to prevent accidental removal in use.

The three bearings for the respective toggle members 42a, 42b and 42c in trip bar 38 are formed by molding openings into the trip bar from the opposite sides of the trip bar. Thus a pair of openings 88 (Fig. 9) are molded into one face of the trip bar and another opening 90 is molded into the opposite face of the trip bar, these openings 88 and 90 being deep enough to provide a continuous endwise passage or hearing for receiving one leg of the element 42a. Similar complementing openings are formed for providing respective bearings for one leg of each element 42b and 420 incommon trip bar 38. Similar axially extending bearings are provided in member 38 by openings moldedinto member 38 from the opposite sides thereof in order to provide respective elongated bearings 40 for elements 36a of the composite actuator.

The operation of the entire circuit breaker may now be summarized as follows:

The circuit breaker consists of three virtually identical poles each having its own operating mechanism and each having its own overload release device. In addition, each of the poles has a release toggle 38-42, with one of the release toggle elements taking the form of a common trip bar extending across all of the poles.

-When the circuit breaker is fully open, as illustrated in Fig. 2, the circuit breaker is in condition for being closed. In that condition, each of the release toggles 3842 is locked or over-set, this configuration being assured by rivet 78 and spring bearing against element 30 of the composite manual actuator. Also, element 36a at each end of trip bar 38 is biased by rivet 78 and spring 80 to the upper extremity of the elongated opening 40 formed'in each end of the trip bar 38. Initial operation of handle 30a counterclockwise in Fig. 2 pushes actuator 56-60 into engagement with the end of current responsive bimetal 62. Thereafter continued thrust of the handle 30a in the contact-closing direction to the left in Fig. 2 causes the elements 50-56-60, and 62 to pivot as a unit about spring 52. Obstruction element 68 engages a shoulder 74 formed in the casing, which arrests the advance of moving contact arm 50 before the contacts engaged. Continued drive'of handle 30a in the closing direction stresses spring 52 which assumes the sagging configuration in Fig. 17. Near the end of the on stroke of handle 30a, handle projection 70 operates spring 72 against the right-hand arm of V- shaped member 68 and shifts that member out of its obstructing position. Spring 52 is then elfective to snap the contacts closed, this spring being stiffer than contact opening spring 72 which opposes such closing operation. When handle 30a completes its on stroke, the locking toggle which may also be called an actuating toggle, consisting of the composite operating elements 28-3032-34-36 as one element and elements 38- 42 as the other element, becomes over-set and locks each pole of the circuit breaker closed, against the opening bias of the several springs 72.

In the event of a sudden overload in any one of the poles, bimetal 62 is deflected downward by attraction to the core 76 and actuator 5660 is released. A more gradual overload causes bimetal 62 to deflect out of engagement with actuator 56-60 to release that overloaded pole. When this occurs, spring pivot 52 in its initially sagging condition straightens quickly and lifts actuator 56 so as toassume the operational position of Fig. 3 in which the contacts are still closed. This action swings trip bar 38 counterclockwise to a suificient extent to buckle the toggles of the adjoining poles, as illustrated in Fig. 5. All of the springs 72 are then elfective to drive the'respective contact-carrying arms 50 in the opening direction. I

During the initial phase of operationrepresented in Figs. 3 and 5, thespring pivot 52 functions (as previclosing mechanism and thereby to insure closing of the contacts. During the reverse operation, as an incident of the release of an overloaded pole, the over-travel spring is eflective to keep the contacts closed during the release of all the release toggles 38-42 of the untripped poles, with the result that springs 72 drive all of the .poles open virtually simultaneously.

The circuit breaker is trip-free, in the sense that the contacts of the overloaded pole as well as the contacts of the poles tripped by the common trip bar are free to open even though the handle 30a is held in its on position. This condition is illustrated in Figs. 4 and 6. When the handle 39a returns to its oil position, either by being returned by springs 72 or by being manipulated into that position, any actuator 56-60 that may have swung to the position in Fig. 4 is returned to the position of Fig. 2 by the tension developed in elements 38 and 42 between elements 36a of the composite operator of the circuit breaker and the bearing 58 of each actuator 5660. The actuators 56-60 of the non-overloaded tripped poles remain in the condition required for reclosing of the circuit breaker.

Springs 72 act on contact arms 50 at a very prominent distance from the respective pivots of the contact arms 50. Therefore the opening force applied to the moving contact arms 50 is reliable and the contacts return to their open position under proper circumstances. However the action of springs 72 against the three elements 28, 30 and 32 is directed relatively close to the pivotal axis of those elements and in consequence handle 30a will be returned toward the oil position only to the extent permitted by a frictional trip-indicating obstruction that may be provided. Under such conditions the partly returned handle 30a is manually reset to oil before the circuit breaker is to be reclosed. If the circuit breaker casing is designed for full clearance, then springs 72 will return the composite operator 28-3(l- 32 3436 and the elements operated thereby to the full position in Fig. 2.

There has been given above the detailed description of an exemplary practical application of the invention in its various aspects, but those skilled in the art will readily appreciate the possibilities of modification and 'varied application of its novel features; and therefore it is appropriate that the invention should be broadly construed, consistent with its full spirit and scope.

What is claimed is:

1. A circuit breaker including an angularly operable first member, a second member, and a connecting device articulated to both said members, said first member having a unitary portion thereof engageable in rolling contact with a unitary portion of said connecting device, and said connecting device and said second member having mutually engaging portions fixing them in normally near-straight condition against collapse in one direction only, and said second member and said connecting device being operable as a unitary link by said first member.

2. A circuit breaker including an angularly operable drive member, a driven member, and a device having captive connections to both said members, said drive member having a unitary portion thereof engageable in rolling contact with a unitary portion of said con necting device, and said device and said driven member having mutually engaging portions fixing them in a normally near-straight condition against collapse in one direction only, and said driven member and said device being operable as a unitary link by said drive member.

3. A circuit breaker including an angularly operable first member, a second member, and a releasable toggle articulated to both said first and second members, said toggle and said first member having respective unitary portions in rolling contact with each other.

4. A circuit breaker including an angularly operable drive member, a driven member, and a releasable toggle articulated to both said drive niemb'erand said drivii *member, said toggle and said drive member having respective unitary portions in rolling contact with each other.

5. A circuit breaker including an angularly operable first member, movable contact means including a second member, and a releasable toggle articulated to both said members, said toggle including a link having an integral portion in rolling contact with an integral portion of one of said members.

6. A circuit breaker including an angularly operable drive member, a movable contact member, and means articulated to both said angularly operable drive member and said movable contact member, said means including a releasable toggle, said drive member and said toggle having unitary portions in rolling contact with each other.

7. A circuit breaker including an angularly operable drive member, a releasable toggle constituting a drive link when locked, and contact-closing mechanism operated by said toggle, said drive member and said toggle having respective unitary portions in rolling contact with each other.

8. A circuit breaker including an angularly operable drive member, contact operating means including a driven member, and a collapsible toggle acting when straight as a drive link between said members, said drive member and said toggle having a pin and a pin receiving recess as the operative connection therebetween, said pin having rolling contact with the wall of said recess during operation of the contact operating means by said driving member.

9. A circuit breaker including an angularly operable drive member, contact operating means, and a collapsible toggle acting when overtoggled and thus locked as a drive link betwen said drive member and said contact operating means, said drive member having a pin and said toggle having a recess receiving said pin, said pin having rolling contact with a bearing wall of said recess during the operative stroke of said driving member, and the degree of overtoggle changing from a large to a small value but not reversing during said stroke.

10. A circuit breaker including an angularly operable driving member, contact operating means including a driven member, and a collapsible toggle acting when locked as a link interconnecting said driving and driven members, said driven member being pivotally connected to one end of said toggle and said driving member being connected to the opposite end of said toggle by means of a rolling pin-and-slot connection.

ll. A circuit breaker including an angularly operable drive member, contact operating means, and a collapsible toggle interposed between said contact operating means and said angularly operable drive member, one end of said toggle being pivotally connected to said contact operating means and the other end of said toggle having a slot formed therein, said drive member having a shaft of circular cross-section extending into said slot and operable in rolling contact against a Wall thereof in operating the contact operating means, said wall having a curvature centered about the pivotal connection of said one end of the toggle.

12. A circuit breaker including an angularly operable drive member, contact operating means operated thereby, and a toggle interposed therebetween and acting as a drive link when the toggle is locked, said drive member and said toggle having a pin-and-slot connection therebetween affording rolling contact in operation and said slot having a bearing wall against which said pin rolls and an end wall defining a limit for said pin, and spring means biasing the pin against said end wall at one end of the angular travel of the drive member.

13. A circuit breaker including drive and driven members, at least one of which operates through an angle, and a toggle interposed therebetween and acting as a drive link when the toggle, is locked, said angularly operable one of said members and said toggle having a pin-and-slot connection therebetween afiording rolling contact in operation and said slot having a bearing against which said pin rolls and an end wall defining a limit for said pin, and spring means biasing the pin against said end wall at one end of the angular travel of said one member.

14. A circuit breaker including a drive member, contact operating means operated thereby, and a toggle interposed therebetween and acting as a drive link when the toggle is locked, and spring means acting between said toggle and a reaction point not on said toggle to bias it into locked state, said toggle being displaced relative to said reaction point during operation of said drive member and the bias of said spring means on said toggle being relieved upon relative motion of said toggle and said reaction point.

- 15. A circuit breaker in accordance with claim 14, wherein said spring means is carried by said toggle and is cooperable as aforesaid with a po'rtion of said drive memher acting as said reaction point.

16. A circuit breaker including an angularl'y operable drive member, a contact operating means, and a collapsible toggle acting when locked as a drive link between said contact operating means and said angularly movable drive member, said toggle having a pivotal connection at one end thereof to said contact operating means and a pin-and-slot connection between said driving memher and said toggle at the end thereof remote from its pivotal connection to said contact operating means, said slot having a bearing wall and a starting wall, and spring means acting on said toggle between its knee and said remote end thereof to bias said pin against the starting wall of the slot and to bias the toggle into its straight or locked configuration.

17. A circuit breaker including an angularly operable drive member, a contact operating means, and a collapsible toggle acting when looked as a drive link between said contact operating means and said angularly movable drive member, said toggle having a pivotal connection at one end thereof to said contact operating means and a pin-and-slot connection between said driving member and said toggle at the end thereof remote from its pivotal connection to said contact operating means, said slot having a bearing wall and a starting wall, and spring means acting on said toggle between its knee and said remote end thereof to bias said pin against the starting wall of the slot and to bias the toggle into its straight or locked configuration, said spring means movable with the toggle and being arranged to react against a portion of the circuit breaker external of the toggle at the start of the operation of said angularly movable member, said spring means being carried out of cooperation with said reaction portion duringthe operation of said drive memberff 18. A circuit breaker including an angularly operable first member, a second member, a connecting device articulated to both said members, said'first member having an unitary portion thereof movable in rolling contact along an unitary portion of said connecting device in one direction during one operating stroke, and spring means acting on said connecting device and arranged to bias the connecting device in relation to said first member to establish an initial relationship betwen the angularly operable first member and the connecting device to assure said rolling contact.

19. A circuit breaker in accordance with claim 18 wherein said spring means is arranged to react between said connecting device and said first member.

20. A circuit breaker including a drive member, contact operating means operated thereby and a toggle interposed therebetween and acting as a drive link when the toggle is locked, and spring means reacting against said toggle and said drive member in the direction to bias the toggle into locked state at one end of the operative stroke of said drive member, said toggle being displaced relative tosaid drive member during operation thereof, and said spring means being thereby displaced to interrupt the reaction thereof between the drive member and the toggle.

References Cited in the file of this patent UNITED STATES PATENTS 448,525 Kennedy Mar. 17, 1891 911,698 Bevan 2. Feb. 9, 1909 1,320,590 Waters Nov. 4, 1919 1,530,227 Bourassa Mar. 17, 1925 2,091,941 Frank Aug. 31, 1937 2,174,232 Baker Sept. 26, 1939 2,195,016. Swingle Mar. 26, 1940 2,210,870 Platz Aug. 6, 1940 2,214,695 Jennings Sept. 10, 1940 2,285,770 Frank et al. June 9, 1942 2,338,097 Cochran Jan. -4, 1944 2,346,643 Barnett Apr. 18, 1944 2,362,257 Favre Nov. 7, 1944 2,388,620 Runke Nov. 6, 1945 2,802,080 Locher Aug. 6, 1957 FOREIGN PATENTS 365,527 Great Britain Jan. 18, 1932' 480,910 Germany Aug. 10, 1929 949,494 France Feb. 21, 1949 1 e wr w Ta-inn. 

